A recording method that uses an ink jet printer, which is a typical one of various color recording methods, includes producing ink droplets and depositing the ink droplets on a recording material (such as paper, film, or textile). This method is silent without sounds caused by direct contact between a recording head and a recording material and can be easily performed in a smaller scale and at a higher speed. Because of these advantages, the method is being rapidly adopted, and usage thereof is expected to increase in the future.
In an ink jet recording method that uses an aqueous ink, in addition to recording materials having an ink-receiving layer, such as ink jet paper and ink jet glossy paper, recording materials having no ink-receiving layer and having low ink absorption ability, such as general-purpose plain paper, can also be used as recording materials.
Among these, recording materials having no ink-receiving layer are impermeable to ink, and most of a colorant remains on the surface of the recording materials. Thus, touching the materials with a finger or rubbing the materials together sometimes results in scratch-related problems, such as easy separation of pigment. This tendency is particularly marked with aqueous pigment inks.
Although water-insoluble coloring matter, such as pigments, are known to resist light, ozone, or water, when an ink comprising a water-insoluble coloring matter is dried, and the coloring matter aggregates, it is difficult to redisperse the coloring matter due to its water insolubility. Because of such characteristics, water-insoluble coloring matter are likely to cause troubles, such as clogging of a printer head. Thus, there is a strong demand for inks having high redispersibility in water even after the inks are dried.
It is proposed to add a particular polymeric material to an ink jet recording ink composition to improve the scratch resistance of the ink composition. In particular, an ink jet ink composition to which resin emulsion is added is proposed. However, it is difficult to achieve sufficiently high scratch resistance and ejection stability.